Stack unwind through a signal frame?

[kf]

Not sure if this is the right forum, but ....

I'm using Suse Linux 10 on x86-64. I've written some routines to unwind the stack using the DWARF information stored in the relevant elf binaries. However, when I hit an RIP value of 0 I'm not certain if I'm at the start of the stack or at a signal stack frame. In the case of the signal stack frame, I can see what looks like a sigcontext on the stack but don't know how to get to it programmatically. So the question is:-
i. How do you recognise a signal stack frame as opposed to an ordinary stack frame ?
ii. How is the signal stack laid out so I can access the faulting context ?

Thanks in advance.

[felPmy]

What version (10.0?), what kernel version (x86_64 or i386), uname -r? Are you able to post the relevant parts of the code? Are running the code in gdb?

[kf]

To determine if I'm unwinding through a signal frame on the stack I check the return address of each stack frame. If it's in the signal trampoline then it's a signal frame. The signal trampoline is identified by the symbol '__restore_rt'. This is what gdb seems to do, so I borrowed it. It's working ok for now, it just feels 'hacky'.